Download DTMF Decoder for iOS to completely redesigned decoder!Turns your iPhone into a simple DTMF decoder. Simply hold the iPhone's microphone near to a clear source of DTMF...
There's even the option of using Multimon NG (Search google). Once downloaded just open the exe up and then type in from your keyboard this command instruction; "multimon-ng -a DTMF" (without quotes)
Obviously make sure you open the program's directory first from command prompt